Compact coupler plug, particularly for a planar broadband lambda probe, that is protected from dust when in a pre-locking position

ABSTRACT

To enable a housing of a coupler plug, especially for a planar lambda probe, made up of  
     the housing ( 2 ), namely a base element ( 3 ) and a cover element ( 4 ) as well as  
     electrical components, that can be inserted and fixed in the housing, and  
     an adjusting element ( 6 ) for a probe, especially a planar broadband lambda probe, which is mounted in the coupler plug ( 1 ) or outside the coupler plug, via a further contact element,  
     the cover element ( 4 ) being attachable over the adjusting element ( 6 ) and having a primary locking mechanism (first latching position) and a secondary locking mechanism (final position) that cooperates with the cover element ( 4 ), to be sealed off at least from dirt and dust even in its first latching position, it is proposed to mount a seal ( 11 ) on the cover element ( 4 ), the seal having sealing lips ( 12 ) that point away from the cover element ( 4 ), the sealing lips, in the first latching position of the cover element ( 4 ), bringing about a sealing connection with the housing ( 2 ).

[0001] The present invention relates to a coupler plug, in particular for a planar lambda probe, made up of

[0002] a housing, namely a base element and a cover element, as well as

[0003] electrical components, that can be inserted and fixed in the housing, and

[0004] an adjusting element for a probe, especially a planar broadband lambda probe, which is mounted in the coupler plug or outside the coupler plug via a further contact element,

[0005] the cover element being attachable over the adjusting element and having a primary locking mechanism (first latching position) and a secondary locking mechanism (final position) cooperating with the cover element.

BACKGROUND INFORMATION

[0006] Coupler plugs of the aforementioned type are usually designed for the connection between a cable harness plug and a lambda probe, the connections in the coupler plug being provided for adjustment, signal, and/or heating of the probe. The lambda probe and the lambda control, in connection with three-way catalytic converters, represent today an effective method for cleaning exhaust emissions. The lambda probe, which, for example, can be inserted into an exhaust system, includes a sensor for determining the oxygen content in the exhaust gas.

[0007] The residual oxygen content is well-suited for use as a measured quantity, and it regulates the air-fuel ratio, because it indicates precisely whether the air-fuel mixture is being completely combusted.

[0008] In this context, the lambda probe supplies a voltage signal, which represents the momentary value of the mixture composition and which follows the mixture changes. The fuel supply to the engine is controlled by a carburation system in accordance with the signal from the lambda probe in such a way that a stoichiometric air-fuel ratio λ=1 is achieved. Heated or unheated probes are used in accordance with the design of the exhaust gas system and the conditions in which they are used. Outside the field of motor vehicles, other applications of the lambda probe include, e.g., regulating gas motors or oil/gas burners.

[0009] In particular, broadband lambda probes are designed in modular form and, in combination with planar technology, facilitate the integration of a plurality of functions. They usually have functional layers, which are made up of a porous protective layer, an external electrode, a sensor film, an internal electrode, a reference gas channel film, an insulation layer, a heating element, a heating film, a resistor or adjusting element, and connection contacts.

[0010] Because broadband lambda probes are made up of the combination of a nernet concentration cell (=sensor cell) and a pump cell that transports oxygen ions, it can measure very precisely, not only in the stoichiometric point at λ=1, but also in the lean and rich ranges.

[0011] Every probe must be individually adjusted. For this purpose, the probe has a built-in resistor (“mini-hybrid”). The adjustment, which is advantageously performed using a laser beam, is made by properly ablating the resistance layer made up of a ceramic substrate, thereby inducing a change in the resistance, so that an adjustment follows.

[0012] One specific embodiment provides for the adjustment unit, i.e., the resistor, to be mounted directly at the probe. A further exemplary embodiment provides for the resistor to be accommodated externally, for example, on a cable harness plug that is coupled to the probe.

[0013] Heretofore, the adjustment has been carried out by transporting the housing of the coupler plug, in which the resistor is embedded, to the adjustment station without the cover element. After the appropriate laser processing for the adjustment, the cover element was mounted at a further assembly station.

[0014] To prevent the ingress of humidity, contamination or the like into the coupler plug, and to assure that the appropriate atmosphere prevails within the coupler plug, the cover element has additional seals. Furthermore, pressure equalizer elements are mounted on the housing of the coupler plug.

DISADVANTAGES OF THE RELATED ART

[0015] However, the seals accomplish their sealing function only if the cover element is latched in its final position (secondary locking mechanism). When the coupler plug is transported to the adjusting station, either the cover element is completely removed, or it rests on the housing of the coupler plug, thus not accomplishing any latching function with the housing, because the cover element must once again be removed in order to adjust the adjusting element. Therefore, the danger exists, especially when the coupler plug is being transported, that dust, dirt, or humidity will penetrate into the housing, thereby impairing the functioning of the coupler plug.

OBJECT OF THE INVENTION

[0016] The object of the present invention is to refine an embodiment of the coupler plug that is provided especially for a planar broadband lambda probe, in such a way that the probe can be manufactured in a very cost-effective manner, and, as a result of the refinement, the disadvantages of the related art are avoided.

ACHIEVEMENT OF THE OBJECTIVE

[0017] The objective is achieved in that a seal is provided on the cover element, the seal having sealing lips pointing away from the cover element, the sealing lips, in the first latching position of the cover element, bringing about a sealing connection with the housing.

ADVANTAGES OF THE INVENTION

[0018] One essential advantage of the present invention is that the coupler plug it proposes is designed to be of small construction, because, due to the compact design, i.e., the insertion of electrical contacts into a base element and the placement of the adjusting element likewise in the coupler plug, the exterior dimensions of the coupler plug, which is advantageously positioned between a cable harness and a lambda probe, are very small.

[0019] In addition, it has proven to be advantageous that the coupler plug proposed here by the present invention has only a small number of components. As a result, a cost-effective and efficient manufacturing process is possible.

[0020] Because the base element is completely enclosed by the cover element, it is possible, by configuring sealing lips within the cover element, to seal off the interior of the coupler plug, thereby protecting it in particular from dust, dirt, or water spray, even in the first latching position of the cover element.

[0021] In addition, this also supports the latching of the cover element to the base element. Advantageously, a first and a second latching mechanism, i.e., a primary and secondary locking mechanism, are provided. The latter is configured such that the cover element has latching arms, which, in the closed state of the cover, contact the base element of the coupler plug and produce a latching there using detents. In the first latching position, the sealing lips mounted on the circumferential seal on the cover element already engage in cutouts on the sides of the housing and therefore provide protection at least against dust and dirt. By once again pressing the cover element in the direction of the housing, the circumferential seal that is mounted in the cover element becomes functional when the final position (the secondary locking mechanism) is reached, and it completely seals the housing from its external environment. The seal is preferably designed so that the housing is watertight in the final position of the cover element. In this final position, the sealing lips cease functioning and are all but completely accommodated in the cutout in the housing.

[0022] A further advantage of the present invention is that the aforementioned seal can be injection-molded on the cover element, so that it is non-detachably mounted.

[0023] The cover element is advantageously made of PBT (polybutylene terephthalt) or a similar material.

[0024] Further advantageous embodiments are derived from the descriptions, claims, and drawings below.

[0025] The following are the contents:

[0026]FIG. 1 depicts a perspective view of the coupler plug according to the present invention, having a cover element in the final position;

[0027]FIG. 2 depicts a perspective view of the coupler plug according to the present invention, without the cover element;

[0028]FIG. 3 depicts a longitudinal cutaway view of the coupler plug according to FIG. 1;

[0029]FIG. 4 depicts a detail representation of FIG. 3, the functioning of the cover element together with the seal and sealing lips being depicted in a cutaway view, and the cover element being situated in a first latching position;

[0030]FIG. 5 depicts a detail representation of FIG. 3, the functioning of the cover element together with the seal and sealing lips being depicted in a cutaway view, and the cover element being situated in a final position.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

[0031] Coupler plug 1, depicted in FIGS. 1 through 5, is a type of plug that is made up of a housing 2, which is composed of a base element 3 and a cover element 4.

[0032] On base element 3, an adjustment unit 6 is mounted in a holding device 5, the adjustment unit in turn being connected via electrical contact elements 7 to the lambda probe that is connected via a connecting element 8, or to the plug that is inserted into coupler plug 1 and is not depicted in greater detail in the drawings.

[0033] Electrical contact elements 7 are made up of metal strips that are shaped like printed circuit traces, which in the area of coupling potential 9 (FIG. 4) of coupler plug 1 terminate in their one side.

[0034] Adjustment unit 6 is guided by guide elements 10, that are mostly configured on base element 3, and the adjustment unit is held in position by electrical contact elements 7.

[0035] Cover element 4 on its interior side has a circumferential seal 11, which, in the assembled state of cover element 4, corresponds to the housing. In addition, sealing lips 12 are mounted on seal 11 so as to point away from cover element 4. These sealing lips 12 taper towards their ends. The length of sealing lips 12 is dimensioned such that, when cover element 4 is placed on housing 2 in the first latching position, depicted in FIG. 4, they extend into cutout 13, so that housing 2 is sealed off.

[0036] By bringing about the final position of cover element 4, as depicted in FIG. 5, the result is that sealing lips 12 are pressed further into cutouts 13, and the actual seal between circumferential seal 11 and housing 2 is accomplished.

[0037] Advantageously, seal 11 and sealing lips 12 constitute a single piece and are injection-molded non-detachably on the interior side of cover element 4.

[0038] Advantageously, coupler plug 1 on its periphery has grooves 14, which permit a coupler plug 1 to be inserted in holders that are provided for this purpose.

[0039] Due to its small exterior dimensions, it is also possible to accommodate the coupler plug in a grooved tube. 

What is claimed is:
 1. A coupler plug (1), especially for a planar lambda probe, made up of a housing (2), namely a base element (3) and a cover element (4), as well as electrical components, that can be inserted and fixed in the housing (2), and an adjusting element (6) for a probe, especially a planar broadband lambda probe, which is mounted in the coupler plug (1) or outside the coupler plug (1) via a further contact element, the cover element (4) being attachable over the adjusting element (6) and having a primary locking mechanism (first latching position) and a secondary locking mechanism (final position) that cooperates with the cover element (4), wherein a seal (11) is provided on the cover element (4), the seal having sealing lips (12) that point away from the cover element (4), the sealing lips in the first latching position of the cover element (4) bringing about a sealing connection with the housing (2).
 2. The coupler plug as recited in claim 1, wherein the seal (11) is fixedly joined to the cover element (4).
 3. The coupler plug as recited in claim 2, wherein the seal (11) is injection-molded onto the cover element (4).
 4. The coupler plug as recited in at least one of the preceding claims, wherein the sealing lips (12) along with the remaining seal (11) constitute a single piece.
 5. The coupler plug as recited in one of claims 1 through 3, wherein the seal (11) and the sealing lips (12) are made of different materials.
 6. The coupler plug as recited in at least one of the preceding claims, wherein, in the first latching position of the cover element (4), the sealing lips (12) penetrate into a cutout (13) that is provided in the housing (2) and lean against the wall of the cutout (13), thus sealing off the housing (2).
 7. The coupler plug as recited in at least one of the preceding claims, wherein, in the final position of the cover element (4), the sealing lips (12) are all but completely engaged in the cutout (13) provided in the housing (2), and the seal (11) itself completely seals off the housing (2). 